Mechanism for operating metallurgical furnace doors



Oct. 30, 1934. p B TQNNAR 1,979,125

MECHANISM FOR OPERATING METALLURGICAL FURNACE DOORS Filed Aug. 6, 1932 2Sheets-Sheet 1 3nnentor P401 3- TOW/V47? altorneg 5 Oct. 30, 1934. P. B.TONNAR 1,979,125

MECHANISM FOR OPERATING METALLURGICAL FURNACE DOORS Filed Aug. 6. 1932 2Sheet-$heet 2 3nnentor PA!!! .B- TOM/VAR BE 1M attornegs UNITED srArssPatented Oct. 30, 1934 PATENT QFFEWZ MECHANISM FOR OPERATING METAL-LURGICAL FURNACE DGOBS Paul B. Tonnar, Cleveland, Ohio ApplicationAugust 6,

Claims.

This invention relates to an apparatus for raising and lowering thedoors of a metallurgical furnace and more particularly to improved meansfor operating the furnace doors of an 'iopen hearth furnace.

Heretofore the apparatus which has been most commonly used for raisingand lowering furnace doors has consisted mainly of a hydraulicallyoperated and controlled type. The use of such apparatus called for anextensive outlay of pipes, valves, pumps and related equipment and inthose installations where water was used as the fluid medium it wasnecessary to provide additional means to prevent the same fromfreezingduring the winter season. Such system, on the whole, was costly toinstall, and

difiicult and expensive to maintain. In other cases, the apparatus forraising and lowering theidoors consisted largely of a winch and speed ,0reducer driven by an electrical motor, one being provided for each doorof the furnace. Such installations were undesirable in view of theinitial and maintenance costs, andthe duplication of motors and speedreducers.

According to the present invention, I have been able to develop a devicewhich solves the aforesaid problems and one which is capable ofoperating a plurality of doors. through a single driven means.

Briefly stated the illustrated embodiment of this invention comprisesashaft driven through suitable driving means and upon which is rotatablymounted a plurality of spaced cable winding sheaves. Disposed on eachside of the sheaves are suitable magnetic means, one of which causes thesheave to rotate with the shaft, and the other magnetic means preventsthe ro tation of the sheave, and maintains the same in a fixed positionduring certain periods in the operation of the furnace doors. Cables areadapted to pass once around the winding sheaves, one end of such cablesbeing secured to the upper portion of the open hearth door, the 5opposite end being suitably counterweighted to offset the weight of thedoor.

Numerous advantageous features more or less ancillary to the foregoingand which are not specifically set forth at this time will become moreapparent as the detailed description of this invention continues, which,considered in conjunction with. the drawings sets forth the preferredembodiment of my invention and wherein:

Figure 1 is a top plan view which diagrammati- 1932, Serial No. 627,795

cally illustrates the adaptation of my invention to an open hearthfurnace.

Figure 2 is a side elevation partly broken away of the deviceillustrated in Figure 1.

Figure 3 is a sectional elevation taken on the line 3-3 of Figure 1.

Figure 4 is a top plan view of the actuating mechanism for raising andlowering a plurality of doors.

Figure 5 is a side elevational view taken on the line 5--5 of Figure 4.

Figure 6 is an enlarged detailed View partly in section of one of thedoor actuating units.

Figure 7 is a modified form of the door actuating unit.

With reference to Figures 1, 2 and 3 there is diagrammaticallyillustrated an open hearth furnace 1 in which my invention has beenincorporated. The open hearth furnace 1 has a plurality of doors 2 whichare adapted to be raised or lowered through the medium of suitablecables 3. These cables have one end secured to and extended from thedoor 2 upwardly and pass over deflecting sheaves 4, across the top ofthe furnace where they pass about deflecting sheaves 5, thence oncearound the winding sheave 6 of my cable actuating mechanism from thenceupwardly and over deflecting sheaves 7 from which they depend, carryingon the end thereof a counterweight. As such times as a door or acounterweight is disposed at their lowermost positions, the windingsheave 6 may be allowed to continue in rotation without fear of overwindas this continued rotation produces a slacking effect in cable 3 aboutthe periphery of winding sheave 6, of the cable actuating mechanism,thereby preventing further travel of the cable 3 and precluding thenecessity of providing limit switches controlling the driving means.

The cable actuating mechanism for raising a plurality of doors isillustrated more in detail in Figures 4 and 5 of the drawings andcomprises a geared speed reducer 9 built integral with a reversibleelectric motor 10. ihis unit is adapted to drive a continuous shaft 11,through the medium of a flanged coupling 12. The shaft 11 is supportedin suitable bearings 12a disposed upon the upper surfaces of transversechannel beams 13. Mounted on the shaft 11 and free to partake ofmovement relative to said shaft are a plurality of winding sheaves 6.These sheaves are preferably disposed in spaced relation and are adaptedto engage cables 3 for raising and lowering the furnace doors.

Disposed in opposed relation on opposite sides of the sheaves 6 aremagnetic field units 15 and 16. The magnetic unit 15 is substantiallycylindrical in shape having an axial extension 17 formed thereon. Themagnet unit 15 is keyed to the shaft 11 and rotates therewith. Theextension 17 carries a collector ring 18 which contacts in any suitablemanner with brushes (not shown) for conveying an electric currentthereto from any suitable source. The collector ring 18 and the brushesassociated therewith are preferably encased in a sheet metal housing 23supported on brackets 24 secured to the channels 13. Carried in suitablerecesses 20 disposed in the unit 15 are a plurality'of electromagnetcoils 21 which have associated therewith friction surfaces 25 engageablewith the side face of sheaves 6. When the coils 21 are energized thebody of the winding sheave 6 constitutes an armature and is attracted tothe electromagnet causing the friction surfaces 25 to engage the sideface of the sheave and to rotate the sheave with the magnet unit whichis secured to the driven shaft 11.

and from any source desired.

the same construction as the rotating unit 15.

This unit includes a plurality of eiectromagnet coils 26 which carryfriction surfaces 27, the latter being adapted to engage the side faceopposite to that which is engaged by the friction surfaces 25. The coils26 may be supplied with an electrical current in any convenient mannerThe unit 16 is preferably immovably secured to the supporting channels13 as at, 28. The unit 16 is effective in maintaining the door in anydesired position, within its limits of travel, without stopping themotor 10, by switching the energizing current from magnet coils 20 tomagnet coils 2 The unit 16 may also serve as a brake to prevent jarringof the door or counterweight at their extreme limits of travel by onlyslightly energizing magnet coils 26 while coils 20 are receiving full ornormal energizing current.

I have elected to describe only one unit in detail and as shown inFigures 1 and 5 a plurality of these door actuating units may be mountedon a single shaft. The shaft '11 may be rotated in either clockwise orcounter-clockwise directions and through energization of theelectromagnet coils 20 carried by the unit 15 the individual dooroperated thereby may be raised or lowered as desired.

With reference to Figure 7 there is illustrated a modified form, of dooractuating unit. In this embodiment there is substituted for the unit 16a disk-like flange plate 30 carrying friction elements 31 adapted toengage the side face of the winding sheave 6. The flange plate is formedwith an axial extension 32 which forms a bearing for the shaft 11. Theplate 30 is preferably immovably secured to the supporting channels 13.A coil spring 33 carried by the unit 15 is disposed about the shaft 11and normally holds the freely movable winding sheave 6 against thefriction elements 31 when the magnet coils 20 carried by the unit 15 aredeenergized. At such time as these coils are energized the attractionfor the sheave 6 overcomes the force of the spring 33 and permits thesheave to rotate with the magnet unit 15.

Although the foregoing description is necessarily of a detailedcharacter, I do not wish to be claims.

I claim:

1. In an apparatus for raising and lowering the doors of a metalluricalfurnace, a cable having one end thereof secured to the door and theopposite end secured to a counterweight, means for actuating the cable,comprising a driven shaft, 2. sheave rotatably mounted on said shaft,means including an electromagnet for operatively connecting said shaftand'sheave, means for preventing rotative movement of said sheave, andmeans carried by said electromagnet for maintaining said sheave inengagement with said last named means.

2. In an apparatus for raising and lowering the doors of a metallurgicalfurnace, a cable having one end thereof secured to the door and theopposite end secured to a counter weight, means for actuating saidcable, said means including a driven shaft, a member keyed to said shaftand rotatable therewith, means engaging said cable carried by said shaftand rotatable thereon, opposed magnetic units disposed about said shaft,

one of said magnetic units when energized adapted to operativelyassociate said cable actuating means and said member to permit said 1100cable engaging means to rotate with said shaft,

the other of said magnetic units when energized adapted to serve as abrake unit.

3. In an apparatus for raising and lowering the doors of a metallurgicalfurnace, a cable hay-i ing one end thereof secured to the door and theopposite end secured to a counterweight, means for actuating said cable,said means including a driven shaft, means engaging said cable rotatablymounted on said shaft, a member keyed to said 110 shaft and rotatabletherewith, magnetic means adapted to operatively associate said memberand said cable engaging means to permit the cable engaging means torotate with the shaft, and a fixed brake member disposed about saidshaft and in opposed relation to said magnetic means, said brake meansincluding an electromagnet having a friction face disposed thereon.

4. In an apparatus for raising and lowering the doors of a metallurgicalfurnace, a cable having one end thereof secured to the door and theopposite end secured to a counterweight, means for actuating said cable,said means comprising a driven shaft, an electromagnet mounted on saidshaft and rotatable therewith, a sheave engaging said cable androtatably mounted on -,ing one end thereof secured to the door and theopposite end secured to a counter weight, means for actuating saidcable, said means comprising a driven shaft, an electromagnetic mountedon said shaft and rotatable therewith, a sheave engaging said cable androtatably mounted on said shaft in close proximity to said magnet, andmeans for energizing said electromagnet whereby thesheave will berotated therewith and brake means mounted concentric with the shaft andengageable with the face of the sheave for prelimited thereby other thanby the appended jventmg rotatlve movement thereof PAUL B. TONNAR.

